As an entire network is based on the Internet Protocol (IP), operators need to perform delay measurement on each Internet gateway (IGW) egress, and select an optimal path according to a measurement result, so as to provide better services for users.
In the prior art, delay measurement manners include a one-way measurement and a two-way measurement. If a one-way measurement is performed on a node A and a node B, a one-way delay from the node A to the node B may be measured, or a one-way delay from the node B to the node A may be measured. If a two-way service policy is performed on the node A and the node B, a delay from the node A to the node B then to the node A may be measured, or a delay from the node B to the node A then to the node B may be measured. The one-way measurement requires that two measured nodes are clock-synchronized and support a same measurement protocol. However, in actual deployment, over the top (OTT) servers generally are not managed by operators. Therefore, an IGW and an OTT server may not support a same measurement protocol. The two-way measurement may determine a two-way delay from an IGW to an OTT server then to the IGW, but an optimal path cannot be calculated on the basis of this measurement result. Therefore, how to accurately measure a delay relationship between delays from an OTT server to different IGWs to determine an optimal path is a problem to be resolved urgently.